Unbeaten welterweight world champion Floyd Mayweather will try to match the iconic 49-0 career record of Rocky Marciano against fellow American Andre Berto on September 12, promoters announced Tuesday.

In what Mayweather claims might be his final fight, and what is the last bout on his rich six-fight Showtime television deal, the reigning World Boxing Association and World Boxing Council champion will risk his crowns against a two-time world champion who has lost three of his past six fights.

"I'm ready to get back in the ring on September 12 and prove again to the whole world why I'm 'The Best Ever,'" Mayweather said. "I always bring my A-game and this fight against Andre Berto is no exception. He's a young, strong fighter who is hungry to take down the best -- 48 have tried before and on September 12, I'm going to make it 49."

Berto, 30-3 with 23 knockouts, intends to flip the script on Mayweather, whose 48-0 record includes 26 knockouts.

"I'm coming to kick Floyd's ass," Berto said. "Best believe I plan to bring it to Floyd and I'm not concerned about what 48 other fighters have been unable to do. Somebody is getting knocked out and it won't be me."

In making the fight, Mayweather snubbed Britain's Amir Khan, 31-3 with 19 knockouts. The Bolton battler has won his past five fights.

Mayweather comes in off his unanimous decision victory over Filipino icon Manny Pacquiao last May and with a goal to equal the 49-0 of the late heavyweight champion Marciano, who retired in 1956 with one of boxing's most hallowed marks.

Mayweather, 38, has won 12 world titles over five weight divisions. He has defeated 22 world champions in his career and has been the world's highest-paid athlete under the TV deal he signed in 2013.

Berto, 31, was a 2004 Haitian Olympian. He won the WBC welterweight crown in 2008 and defended it five times before losing it in 2011 to American Victor Ortiz, only to claim the International Boxing Federational version of the crown later the same year by stopping Slovenian Jan Zaveck.

But Berto lost his next two fights, to American Robert Guerrero by unanimous decision and Mexico's Jesus Soto by 12th round knockout.